Prior to this weekend, I had never thought it was possible for a type O parent to have a type AB child. I guess there are exceptions to this though. My husbands step mother was just diagnosed with colon cancer last July. She told me this past weekend that her blood type was O+. Her daughter had told me over Thanksgiving that she was AB+. There is absolutely NO chance the 2 are not related because they both look soooo much alike. After searching on the internet, I found some information that said that it IS possibly but very very rare. I had never heard this before. Genetics sure is interesting.

first make sure she is typed right.

Lola's got a good(!) point...

Interesting....So being an AB myself, what combination could my parents be??? I have no clue other than my sister thinks she's an O  

I would have the person be retyped.  I've heard of rare situations where the blood type has changed, but they were something else to begin with.

 Girly, if you are an AB then your parents could either be, A, B, or AB.  They couldn't be an O.

Quoted from KimonoKat

I would have the person be retyped.  I've heard of rare situations where the blood type has changed, but they were something else to begin with.

 Girly, if you are an AB then your parents could either be, A, B, or AB.  They couldn't be an O.

and one of them..( or both) must be a non-secretor because I am ...right??

possibly but not necessarily....

non of my kids are nonnies, for example.

I wish I could find the interactive chart that I had on my old computer before it crashed, but here are a couple charts that I found just now that might be helpful:

http://mistupid.com/health/bloodinherit.htm
http://www.dnatesting.com/resource/aboBloodTypeCalculator.php

Quoted from girly

and one of them..( or both) must be a non-secretor because I am ...right??

Non-secretor is recessive, both parents could be secretor but carry the non-secretor gene. Like a red head child from brown haired parents.

Sometimes genetics do get mixed up. Two blued eyed people are supposed to produce blue eyed children since the phenotype for blue eyes is two recessive alleles and the parents only have recessive alleles to give off. However my ex boyfriend had two blued eyed parents and he has one blue eye and one green eye. Green is a dominant gene so I don't understand that at all. (NOTE: this is not true for dominant colors. Two brown eyed parents can have a blue eyed child so long as they carry the gene as only one dominant allele is necessary to have that trait.)

Quoted from macawluver

Prior to this weekend, I had never thought it was possible for a type O parent to have a type AB child. I guess there are exceptions to this though. My husbands step mother was just diagnosed with colon cancer last July. She told me this past weekend that her blood type was O+. Her daughter had told me over Thanksgiving that she was AB+. There is absolutely NO chance the 2 are not related because they both look soooo much alike. After searching on the internet, I found some information that said that it IS possibly but very very rare. I had never heard this before. Genetics sure is interesting.

The condition is called cis AB and it is most common in Japanese and other Asian populations. It results when an individual inherits a gene for group O on one chromosome and another mutated gene that is capable of producing both A and B transferases, thus creating both A and B antigens. Their are also other mechanisms by which cis AB results.One is an unequal crossing over.

Here is a link of a story of cis AB. The patient in this case typed as AB, but had a very weak reaction with the anti B typing serum and produced a weak anti B antibody.
http://bja.oxfordjournals.org/cgi/content/full/94/6/733

and another from the Annals of Clinical Laboratory Science
http://www.annclinlabsci.org/cgi/content/abstract/34/4/437

amazing!